1. Field of the Invention
The present invention relates a multiple resolution image sensor and control method, more particularly, a multiple resolution image sensor for utilizing an effective sensing area inter-leaving each color sensor and control method thereof.
2. Description of the Prior Art
A scanner is currently a very common peripheral product that is used for scanning documents and generating corresponding image data. Additionally, the scanner can provide functions such as using a phone line to transmit the image data to a fax machine, connecting to a network and transmitting the image data using electronic mail, or connecting to a printer to generate output.
Please refer to FIG. 1 and FIG. 2. FIG. 1 illustrates a prior art diagram of a scanner 10. FIG. 2 illustrates a functional block diagram of a scanner 10. The scanner 10 comprises a casing 12, a control circuitry 22 for controlling operation of the scanner 10, a scan module installed within the casing 12, a stepper motor installed within the casing 12 that is situated between and coupled to the control circuitry 22 and the scan module 18. As shown in FIG. 1, a platen 14 is placed on top of the casing 12 for scanning a document 16. When the scan module 18 is scanning the document 16, the control circuitry 22 controls the stepper motor 20 using a stepping method to drive the scan module 18 to scan a document 16 from the beginning to the end.
Please refer to FIG. 3. FIG. 3 illustrates a prior art diagram of a color sensor of a scan module 18. The scan module 18 typically has three rows of color sensors; a first color sensor 24, a second color sensor 26 and a third color sensor 28. The first color sensor 24, the second color sensor 26, and the third color sensor 28 are red, green, and blue respectively. As the document 16 is scanned each color sensor senses the reflected red light, the reflected green light, and the reflected blue light. A single color sensor is capable of sensing a light signal of a single sub-pixel. Three different light signals, of normal light, combine to form a pixel. For example, sub-pixel R11 of the first color sensor 24, sub-pixel G21 of the second color sensor 26, and sub-pixel B31 of the third color sensor can combine to form the first pixel 30; sub-pixel R12, sub-pixel G22, and sub-pixel B31 can combine to form the second pixel 31, and so forth. Resolution of the scan module 18 is calculated by the number of pixels detected on unit area of the first color sensor 24, the second color sensor 26, and the third color sensor 28. For example, if the scanner 10 has a resolution of 600 dots per inch (dpi) and 1200 dpi, that means that the first color sensor 24, the second color sensor 26, and the third color sensor 28 of the scan module 18, each has 600 or 1200 sub-pixels per inch and all three sensors combine for a resolution of 600 or 1200 pixels per inch.
Please refer to FIG. 4. FIG. 4 illustrates a prior art diagram of the color sensor of scan module 33. The scan module 33 comprises a row of color sensors formed by the inter-leaving of the first color sensor 24, the second color sensor 26, and the third color sensor 28. The sub-pixel R11 of the first color sensor 24, the sub-pixel G12 of the second color sensor, and the sub-pixel B13 of the third color sensor can combine to form the first pixel 34; sub-pixel G12, B13, and R14 can also combine to form a second pixel; sub-pixel B13, R14, and G15 can combine to form a third pixel 38, and so forth. In comparison with the prior art mentioned above, if the scanner has a resolution of 600 or 1200 sub-pixels per inch then utilizing the present invention capturing pixels the resolution should increase by three times its normal dpi. The present invention capturing pixels generates this resolution by repeating the inter-leaving, for example, 1800 dpi (600 dpi*3) and 3600 dpi (1200*3). Although this method of arrangement utilizes the same quantity of color sensors to achieve a higher density there is a need to inter-leave the first color sensor 24, the second color sensor 26, and the third color sensor 28. This inter-leaving process is difficult and costly.